Radioreceiver



@Ct. 15, 1935. p WUERFEL 2,017,085

RADIORECEIVER Filed Oct. 31, 1933 2 Sheets-Sheet 1 k noun HM- J PM N I w- INVENTOR Robert P. Wuerfel BY ZTTORNEYS Oct 1935' R. P. WUERFEL 2,017,05

RADIORECEIVER Filed Oct. 31, 1933 2 Sheets-Sheet 2 L57 WM g8 H INVENTOR k Robert P. Wuevfiel Patented Oct. 15, 1935 UNETED STATES PATENT OFF-ICE 6 Claims. (0,1. 250-27) This invention relates to a radio receiver, and particularly to a radio receiver in which the circuits and apparatus are so designed and assembled that the receiver will not only be highly efiicient in operation but will be very compact.

A feature of the invention is the arrangement of circuits and tubes whereby each tube will perform several functions.

Another feature of the invention is the arrangement of circuits and tubes whereby only two electron tubes will perform the functions of a radio frequency amplifier, a detector, an audio frequency amplifier, a second audio frequency amplifier, and a rectifier.

Another feature of the invention is the circuit arrangement for the use of a tube which may be used to perform the functions of a rectifier and an audio frequency amplifier.

Another feature of the invention is the circuit arrangement whereby the receiver may be operated from alternating or direct current and the functions of the tubes will be the same in either case.

' Another feature of the invention is the circuit arrangement fora tube which will permit it to operate as a radio frequency amplifier, a detector,,and an audio frequency amplifier.

Another feature of this invention is the circuit arrangement which permits a tube which constitutes a regenerative detector, to be coupled .directly to an antenna, but to be effectively isolated therefrom. In designing radio receivers, it has heretofore been the general practice to employ a single tube for each function to be performed by a tube in the receiver. This not only requires a large number of tubes, but makes the assembled receiver bulky. It also increases the amount of wire necessary to connect the various elements .of the re,- ceiver, and complicates the wiring.

In this invention the usual functions of several tubes in the ordinary radio receiver are combined in .a single tube. The size .of the assembled receiver is accordingly greatly reduced as compared with prior art practices, and .thewiring is considerably simplified.

Referring to the drawings:

Fig. 1 is acircuit diagram of thereceiver of my invention; and '7 Fig. 2 is an equivalent circuit diagram which will assist in explainingits operation.

In Fig.1 an antenna I is connectedto ground 2 through a coil 3 and a condenser 4. Thecoil 3 is the primary of a transformer 5 Whose secondary 6 isconnected across a tuning condenser 1. Ba-

dio signals received on the antenna i are impressed through the tuned circuit 6, 'I, and a condenser 8 on a control grid 9 of an electronic tube It. The control grid 9 is connected to ground through resistances II, l2 and I3. The midpoint of resistances II and I2 is connected to ground through a condenser I4, and the midpoint of resistances I2 and I3 is connected to ground through a condenser I5. The tube It has a filamentary heater I6 and a cathode H which is grounded as shown, or through a resistor, with a condenser .in parallel thereto, to provide a bias. The received radio signals are therefore impressed across the control grid 9 and cathode .I'I which constitute one pair of input electrodes for {-5 this device. The tube It has also an anode I8 and screen grid I9. The screengrid is connected through a resistance 211 to the circuit which supplies plate potential to the plate I8 and is ac- 'cordingly suitably biased. This screen grid is ,9 also connected to ground through a condenser 2 I. The plate I8 and cathode l'l constitute a pair of output electrodes for the tube It and are connected through a coil 22 and condenser 5d. The input electrodes 9 and I I and the output elec- 25 trodes l8 and Il with their associated circuits, constitute a radio frequency amplifier for the received radio signals.

Inductively coupled to the coil 22 is a second coil ztwhich is in parallel with a second tuning condenser 24. One side of the tuning condenser 24 is connected to ground and the other side is connected through a condenser 25 and parallel grid leak 2 6'to a second grid .27 in the tube II]. The tuning circuit 23, .24, .is therefore connected across the electrodes 21: and I7 and constitutes a second input circuit for the tube It! for .the amplified radio frequency currents in the output circuit between the electrodes I8 and I1. A second anode 28 is also enclosed in the .tube II This anode is connected to the midpoint of resistances I2 and I3 through a condenser 29 and is connected to ground through a resistance 39 and condenser 3|. The input electrodes 2i and IT and output electrodes 28 and H and their associated circuits therefor constitute a detector for the amplifiedradiofrequency currents.

AudioTfrequency currents in .the output circuit of the detector .whose output electrodes are 28 and I! are now supplied through condenser 29 and resistances I2, .I I, and I3 .to the input electrodes 9 and I! previously described. The input electrodes Qand .I] and output electrodes I8 and .I] now act .to amplify the detected audio frequencysignals, so this same tube 19 again functions, this time as an audio frequency amplifier. The coil 22 is connected to the anode I8 as previously described. The other side of this coil is connected through resistance 32 to condenser 3i and through condenser 33 and resistance 34 to the grid 37 of a second electron tube 53.

This electron tube has an anode 36, a grid 31, an anode 33, a filamentary heater 4! and two cathodes 38 and 48, and the tube functions in this circuit as an audio frequency amplifier and as a rectifier. The elements of the tube performing these two functions are physically separated within the tube with one filamentary heater 4| heating their respective cathodes 33 and 48.

The grid 37 is connected to ground through resistance 35 and condenser 46, and the cathode i6 is grounded. Grids3l and cathode 38 constitute the input electrodes, and anode 36 and cathode 38 the output electrodes for the audio frequency amplifying portion of this tube. The audio frequency amplifying'portion of tube [8 is coupled through resistances 32 and 35 and condenser 33 to the audio frequency amplifying portion of tube 53. Connected to anode 36 is a voice coil 48'for operating a loud speaker illustrated diagrammatically at'49, and'the coil 48 is connected to ground through resistance 4'! and condenser 3|.

The rectifying function of this tube is performed by the anode 39 and cathode 40. The anode 39 is connected to one side 54 of a power line to which the circuit of the radio receiver may be connected by means of plug 52 which is adapted to fit an ordinary power outlet from the usual house circuit. The anode 39 is by-passed to ground by a condenser 56. The other side 55 or the power line is connected through a filter condenser 42 to the cathode'46. The cathode 48 is connected to ground through a second filter condenser 43. A resistance 44 is connected across the condensers 42 and 43 and the midpoint ofthis resistance is connected to condenser 4 through a resistance 45.

The filamentary heaters of tubes l8 and 53 are connected in series across the power line through a resistance 5i. The circuit forthese filamentary heaters is indicated near the bottom of Fig. 1 which shows that the circuit runs from the side 54 of the power line through resistance 5|, and through filaments l6 and 4| in series to the other side 55 of the power line. Tube 53 may be comprised of two separate tubes, one containing elements 31, 36 and 38, and the other elements 39 and 46, in which case their heaters would be connected in series.

Condensers I4, I5 and resistance l2, comprise a radio frequency filter, which may be replaced by any other suitable form of radio frequency filter.

Condenser. 54 and resistance 34 comprise a radio frequency filter to the grid 38 of tube 53.

Condenser 46, and resistor 45 form a hum or ripple filter to grid 37 of tube 53. ,7

Condensers 42 and 43 with resistor 44'constitute the filter system which in Fig. '1 is shown in the negative side or negative leg of the circuit. This filter system may be placed in the positive leg of the plate supply circuit, if desired, as shown in my copending application Serial No. 652,812, filed January 21, 1933.

In the operation of the receiver the plug 52 will be inserted in a power socket. is direct, the upper prong of the plug must make connection with the high potential side of the line. This may be determined by simply insert- If the current ing the plug and waiting for results, as no injury will be done if the plug is inserted with the upper prong connected to the low potential side. If the current is direct, a positive potential will be impressed on the anode 39, current will flow 5 between the anode 39 and cathode 43, and positive potential will be impressed on the anode 36 through coil 48. If the current of the power circuit is alternating, an alternating potential will be impressed upon the anode 39 and will be 10 rectified between the anode 39 and cathode 40,

" and in this event a direct current potential will also be impressed upon anode 36 through the coil 48. In either event the direct current from the rectifier having electrodes 39 and 48, will 15 pass through the resistance 41 and a direct current potential will be impressed upon the anode 58 through resistance 32, upon the anode 28 through the resistance 38, and upon the screen grid l3 through resistance 28. 20

The operation of the circuit may be better understood by the equivalent circuit diagram shown in Fig. 2. In this figure the electrodes in the tubes and the associated circuits which perform the functions heretofore stated, are shown 5 as though they were in separate tubes and the circuit elements repeated where necessary to indicate their functioning in the circuit. Thus it will be seen from this figure that the received radio signals are impressed upon input electrodes 3 and ll of tube I6 across the tuning circuit 6, l. The radio frequency currents are amplified in the tube and supplied inductively to the electrodes 21 and Il'of the same tube l0 across the tuned circuit 23, 24 through the condenser and 5 associated grid leak 25, 26. Here the radio signals are detected and the output across electrodes ll is supplied through resistance coupling to the input electrodes 9 and I! of tube H], which thistime function as part of an audio frequency 40 amplifier. The output across electrodes I 8 and 5? is supplied through resistance coupling to the input electrodes 31 and 38 of the second tube 53. The audio frequency currents are amplified in this tube and supplied to the voice coil in the out- 45 put circuit across the electrodes 36 and 38. The power circuits will be clearly understood from the description in connection with Fig. 1, and need not be repeated here.

What is claimed is:

1. .A radio receiver comprising an electron tube having a filamentary heater, a cathode, a grid, a screen grid, an anode, a second grid and a second anode, an antenna, a plurality of input circuits signals from said antenna across said grid and cathode whereby said signals are repeated across said anode and cathode, means for impressing 0 said repeated signals across said second grid and. cathode whereby said signals are detected across said second anode and cathode, and means for impressing said detected signals across said grid and cathode whereby said detected signals are 5 repeated across said anode and cathode.

2. A radio receiver comprising an electron tube having a filamentary heater, a cathode, a grid, a screen grid, an anode, a second grid and a second anode, an input circuit connecting said grid and 7 cathode, an output circuit connecting said anode and cathode, means for impressing radio signals across said input circuit whereby said signals are amplified in said output circuit, a second input circuit across said second grid and cathode.

means for supplying said amplified signals to said second input circuit, a second output circuit across said second anode and cathode, means for detecting said signals and supplying said detected signals to said second output circuit, a third input circuit across said grid and cathode, means for supplying said detected signals to said third input circuit, a third output circuit across said anode and cathode, and means for amplifying said detected signals and supplying them to said third output circuit.

3. A radio receiver comprising an electron tube having a filamentary heater, a cathode, a grid, a screen grid, an anode, a second grid and a second anode, an input circuit connecting said grid and cathode, means for impressing radio signals on said circuit, an output circuit connecting said anode and cathode, means foramplifying said radio signals and supplying them to saidoutput circuit, a second input circuit across said second grid and cathode, inductive means coupling said output circuit with said second input circuit, a second output circuit connecting said second anode and cathode, means for detecting said radio signals and supplying them to said second output circuit, a third input circuit connected to said grid and cathode, resistance means coupling said second output circuit with said third input circuit, a third output circuit connecting said anode and cathode, and means for amplifying said detected signals and supplying them to said third output circuit.

4. A radio receiver comprising an electron tube having a filamentary heater, a cathode, a grid, an

for amplifying said signals and repeating them in said output circuit, means for impressing alternating current across said second input circuit, means for rectifying said current, means for impressing said rectified current on said second output circuit, a second electron tube in said receiver, input and output circuits for said second tube, and means for impressing said rectified current on said output circuit of said second tube.

5. A radio receiver comprising a first electron tube having a filamentary heater, a. cathode, a grid, an anode, a second cathode, and a second anode, an input circuit connecting said grid and cathode, an output circuit connecting said anode and cathode, means for impressing audio frequency signals on said input circuit, means for amplifyingsaid signals and repeating them in said output circuit, means for impressing alternating or direct current across said second cathode and second anode, a second output circuit across said second cathode and second anode, means for deriving direct current in said second output circuit, a second electron tube, input and output circuits for said tube, and means for supplying said direct current to said-output circuits of said tubes.

6. A radio receiver comprising an electron tube having a plurality of electrodes, a filamentary heater for said tube, a plurality of input and output circuit-s connecting said electrodes, means for impressing radio signals on said tube, means for operating said tube as a radio frequency amplifier, a detector and an audio frequency amplifier, a second electron tube, a plurality of electrodes in said second tube, a filamentary heater for said second tube, means for operating said second tube as an audio frequency amplifier and as a rectifier, a power source, and means for connecting said filamentary heaters across said power source in series.

ROBERT P. WUERFEL. 

